Once the eye-popping technology of the future, QR codes have become the Rodney Dangerfield of the mobile world – they get absolutely no respect. Business2Community recently asked if QR codes are outdated, Forbes has weighed in on why they don’t work, and AdAge recently pronounced them dead, helpfully offering new technologies and apps “that will surely supplant QR codes, permanently.” And, for good measure, a Twitter user this week tweeted an amusing flowchart of QR code best practices.

I don’t agree. QR code usage has been disappointing, to be sure, and the aging barcode technology clearly is threatened by newer offerings that may be more appealing to consumers and easier to use. But savvy mobile marketers can still use QR codes as a powerful marketing tool, and those odd-looking squares aren’t going away soon.

What’s holding QR codes back?

Much of the blame behind the lack up uptake can be directed at advertisers themselves, who have embraced QR codes without thinking about how they work or why consumers might use them. I’ve seen QR codes on the back of city buses and the backs of workers’ T-shirts, where they’re nearly impossible to scan. They oftentimes direct users to websites that aren’t optimized for mobile, and they rarely present something of value – a promotion offer, for instance, or an interesting video clip – that rewards consumers for taking the time to scan them. And even today I constantly see QR code displays that don’t tell consumers exactly how – or why – to use them. Meanwhile, the smartphone penetration rate in the U.S. stands at about 57 percent, according to recent data from comScore, which means that nearly half of all consumers can’t easily use a QR code.

But a survey by Pitney Bowes of U.S. consumers found that QR codes are seeing respectable uptake anyway. As eMarketer reported, 39 percent of 18- to 24-year-old respondents said they scanned a QR code in a magazine last year; 36 percent of 25- to 34-year-olds had done the same. A comScore survey of users in five major European markets found that QR code usage had essentially doubled from July 2011 to July 2012. QR codes may never catch fire, but they’re catching on.

A powerful – if imperfect — weapon

And while QR codes admittedly aren’t the most efficient technology around – consumers must first download the app, then scan the code to be directed to a website – no other technology or app has the reach or universality QR codes claim. NFC shows tremendous promise as a way to transmit data quickly with a single tap, but penetration rates of NFC-enabled handsets is still very low. Augmented reality apps like blippar can be undeniably compelling, but none has gained any real traction. And although 2D scanners like ShopSavvy have attracted millions of shoppers, they don’t offer the broader functionality of QR codes.

For advertisers, there’s still a lot to like about QR codes. They’re relatively cheap to deploy, can be placed almost anywhere (which isn’t to say they should be placed almost anywhere), and can engage the young, tech-savvy users marketers salivate over.

QR code technology isn’t the mobile marketing panacea some may see it to be, and savvy advertisers should consider several factors when including them in their marketing campaigns.  QR code displays should be clearly marked, they should tell consumers how and why the barcodes should be scanned, and they should reward the consumers who take the time to do so. Marketers who invest the resources to deploy quality QR code campaigns have a chance to create a dialogue with consumers in a way that few other technologies can deliver. Those who fail to leverage the power of QR codes will miss a huge opportunity to engage consumers on the gadgets they carry in their pockets and purses every day.